A popular non-volatile solid state memory in use today is flash memory (both NAND and NOR types). Flash memory is characterized by not being “write-symmetric” when writing data. To illustrate, each cell of a flash memory can be written from a value of “1” to a value of “0” independently of other cells. However, to change a cell back to a value of “1” a relatively large group of cells (called an “erase block”) are set to a “1” value as a group. An erase group might contain hundreds of kilobytes or even several megabytes, and flash management systems that manage frequent updates of small chunks of data may implement relatively complex logic to preserve valid data that may be stored at other locations in the erase block.
In recent years several new “write-symmetric” non-volatile memory technologies have been introduced that do not have the non-symmetry as described for flash memory, such as Resistive RAM (also known as RRAM or ReRAM), and Magnetic RAM (also known as MRAM), as illustrative examples. In these technologies, a cell may be written in both directions—from “1” to “0” and from “0” to “1” without imposing a similar operation on cells that neighbor the cell being written.
Errors may occur in data stored into non-volatile memory devices, such as when a “target” block of a ReRAM experiences a relatively large number of program operations without program operations or erase operations being perfoimed on a neighboring block. In such cases, data stored in the neighboring block may experience errors, referred to as “erase disturb.” Error correction coding (ECC) may be used to correct erase disturb errors and other errors in data read from a non-volatile memory, up to a correction capability of an ECC scheme. Reducing a number of errors in data read from the non-volatile memory may improve read latency due to reduced ECC processing of the data, enable reduced complexity, power consumption, and cost associated with ECC processing circuitry, enable a longer useful life of the non-volatile memory device, or a combination thereof.